The specific aims are to determine whether the hormonal responses to leuprolide acetate (Lupron) will distinguish among the causes of hypo- gonadism in preteen children with hypogonadism, among the causes of precocious puberty, and among the causes of inappropriate puberty. In the latter regard, girls will be compared to adult women with polycystic ovary syndrome to determine whether they have similar ovarian dysfunction, and boys with gynecomastia will be evaluated to test the hypothesis that gynecomastia occurs in boys who produce higher levels of estradiol relative to testosterone than normal.